Lottery scratch-off or instant games have become a time-honored method of raising revenue for state and federal governments the world over. Indeed, the concept of hiding indicia information under a Scratch-Off-Coating (SOC) has also been applied to numerous other products such as commercial contests, telephone card account numbers, gift cards, etc. Literally, billions of scratch-off products are printed every year where the Scratch-Off-Coatings (SOCs) are used to ensure that the product has not been previously used, played, or modified. Typically the indicia are printed using a high speed ink jet printing process, which uses a dye base, water soluble ink system. Thus, ensuring that the printed indicia cannot be read or decoded without first removing the SOC is paramount to ensure that a game or product is secure.
Unfortunately, there are known techniques (e.g., wicking, vapor, steam, etc.) that can be used to diffuse the variable, water soluble, ink jet indicia through the substrate backing or the front SOC. When utilized successfully, these techniques can allow an observer to temporally determine if a given ticket is a winner or non-winner leaving little or no trace of the security breach. Therefore, these diffusion techniques could allow a retailer to identify all winning tickets in a pack, only selling the losing tickets to an unsuspecting public.
In addition to diffusion techniques, electrostatic charges can be applied to an instant ticket with an intact SOC, which under some circumstances creates a differential charge in the hidden ink jet indicia. If an indicia differential charge is achieved, fine powder aspirated over the SOC will align with the hidden indicia allowing for the indicia to be read over an intact SOC, again allowing winning tickets to be identified. When the charge is removed and the powder brushed away, no indication remains that the ticket's integrity was compromised.
Finally, there are techniques for inducing fluorescence in the ink jet indicia dye on the tickets in the infrared (IR) wavelength range that under some circumstances can be detected through an intact SOC with IR sensitive devices (e.g., infrared night vision goggles), yet again allowing winning tickets to be identified without leaving a trace.
Of course, all of the above indicia compromise techniques have associated security countermeasures that have been painstakingly developed over the years to reduce or eliminate errant detection of unplayed winning tickets or documents secured by a SOC. Typically, these security countermeasures involve adding blocking layers of inks that effectively seal the indicia in a protective cocoon. However, these blocking layers are susceptible to intermittent failures, especially when the blocking layers are applied with too thin or with an erratic deposit on the substrate. Additionally, the added blocking layers of security ink(s) require large and expensive printing presses, with typically an additional press printing station required to print each added ink security layer. Indeed, in some embodiments, these added ink security layers could total four or five additional ink film applications, resulting in a significant increase in printing complexity and costs. Furthermore, these added security layers tend to dull the appearance of the printed product, thereby reducing its marketability.
On a conceptual level it can be seen that all of these techniques for security compromises are a direct result of the ink jet indicia being comprised of a printing dye rather than a traditional ink—a printing dye being an entirely liquid medium that stains or colors the substrate and coatings to which it is applied as opposed to an ink that carries solid pigments that are deposited on the substrate and coatings. Thus, the term ‘ink jet’ is somewhat of a misnomer, with ‘dye jet’ being a more accurate (albeit not commonly used) description. The reason that indicia embodied as dye fosters security problems, is that the dye staining its substrate is inherently susceptible to chemical attacks that re-liquefy it thereby allowing for dye migration or diffusion. Furthermore, the long molecular chains of Volatile Organic Compound (VOC) dyes (typical of traditional variable ink jet indicia systems) can be more susceptible to fluorescence especially after the dye has dried on a substrate. Printing inks, on the other hand, are liquids that suspend solid pigmented particles in a liquid medium. With pigmented inks the color and definition is achieved by the pigment residue that resides on the substrate after the liquid carrier is evaporated or altered to a solid state. This solid pigmented ink film residue is inherently resistant to migration attacks, since the solid particles tend to stay put after being applied and cured. Furthermore, the use of pigment particles can potentially reduce the differences in electrostatic charges as well as fluorescence.
In addition to dye based retailer pick-out security problems in the variable indicia discussed above, the relatively low resolution (e.g., 120 or 240 dots per inch—‘dpi’) of existing variable indicia in lottery tickets and other SOC secured documents have allowed additional security vulnerabilities to persist in both consumer fraud and retailer pick-out.
Recently, barcodes permitting automatic ticket validation have been printed under the SOC, with the concept being to allow for automated ticket redemption by reading the barcode (as disclosed in U.S. Pat. No. 6,308,991) that would only appear after the SOC was removed. Typically, these validation barcodes are of a two-dimensional format to compensate for debris left on the validation barcode after partial removal of the SOC. However, these relatively large two-dimensional barcodes introduce new security problems. For example, the large space and redundant nature of two-dimensional barcodes allow for a small portion of the barcode to be exposed to supply sufficient information to determine if a ticket is a winner. While this attribute is desirable for automated validation purposes, the higher contrast requirements of two-dimensional barcode scanning sometimes requires for lower opacity layer(s) to be omitted in the area of the barcode. These omissions of security layers can make the barcode susceptible to candling and diffusion attacks.
Consumer fraud is a different matter, in consumer fraud the security vulnerability is a direct result of the lower resolution indicia requiring a high contrast with their background to be identified on sight. In other words, lower resolution variable indicia require a higher contrast background that typically results in the indicia being printed as isolated islands with no background graphics. This in turn, results in a susceptibility to a consumer cutting indicia out of losing lottery tickets and pasting the cutout indicia together to create an apparent fraudulent winning ticket composite. To complete this scenario, the boxed digit and/or SOC validation barcode areas are also destroyed by excessive scratching such that the ticket will no longer validate through a central site system—i.e., the boxed digit or validation barcode is destroyed such that a central site validation system would have insufficient information to authenticate the composite ticket. Thus, an apparent winning ticket from a visual inspection could be accepted for fraudulent payment by a retailer for its fabricated face value. In the past, varying Benday patterns have been display printed (e.g., flexographic, offset, etc.) in the ticket's scratch-off background as a countermeasure to this aforementioned cut and paste attack. However, since the Benday patterns are display printed, they repeat thereby only hampering and not eliminating the cut and paste attack. Additionally, Carides et al. (U.S. Pat. No. 5,769,458) discloses variable Benday patterns, as well as Rich et al. (U.S. Pat. No. 5,863,075). However, both patents address variable Benday patterns with hidden messages. Additionally, the Benday patterns tend to detract from the appearance and marketability of the ticket/document as well as reducing the contrast and readability of the low-resolution variable indicia.
Therefore, it is desirable to develop methodologies for ensuring the integrity of tickets/documents with SOC protected indicia by incorporating pigmented variable indicia (i.e., true ‘ink jet’) rather than traditional dye based variable indicia. Additionally, these developed methodologies should also incorporate higher resolution variable indicia imaging and possibly new (e.g., nano-pigmented) as well as fewer security ink coatings.